1. Technical Field
This invention relates to the manufacture of multilayer co-fired ceramic substrates for packaging integrated circuit chips, and more particularly to a unique pallet for drying green ceramic cards used in making such substrates.
2. Description of the Prior Art
Techniques for manufacturing multilayer ceramic cards that are used for the above substrates in the electronic industry are well known in the art. U.S. Pat. No. 4,539,058 to Burgess et al., and U.S. Pat. No. 4,497,677 to Sanada et al. are two references that discuss such techniques.
In general, multilayer ceramic cards are made from green sheets of ceramic material. (The term "green" refers to unfired ceramic bodies.) Each green sheet contains a plurality of spaced apart product sites. The sheets are made by forming a slip from a mixture of ceramic powder, organic binder, and solvent. The slip can be cast onto a suitable sheet material and dried. The green sheets, after blanking, are then stacked, processed and laminated. The product sites are cut from or punched out of the laminated stack and sintered.
In accordance with prior art methods, the green sheets are transferred through dryers by continuous type belts. Such techniques require manual loading and unloading. Since the green sheets are fragile and easily broken and torn, manual handling results in high production losses and costs. In addition, contamination is transferred from the belt to the green sheet. Attempts at automatic loading and unloading of these belts have produced smears and product contamination due to the sliding of the part on the moving belt during part removal.